1. Field of the Invention
The present invention relates to electromagnetic relays and more particularly, to relays having improved voltage breakdown characteristics.
2. Description of the Related Art
A typical electromagnetic relay generally includes a bobbin having a winding, a magnetic core disposed within the winding, and an armature mounted for movement at one end of the winding. A movable contact is typically linked to the armature. Pivot motion of the armature in response to electromagnetic forces produced by the winding and core causes the movable electrical contact to make or break electrical contact with one of a plurality of stationary contacts. As such, electrical connection is selectively made between one of the stationary contacts and a terminal point connected to the movable contact member to perform switching functions.
An exemplary relay of the above-noted type is disclosed in U.S. Pat. No. 5,151,675, assigned to the assignee herein, which is directed to an electromagnetic relay having a contact spring mounted on an armature with improved spring flex to obviate problems of welding or adhesion of the electrical contacts. The improved spring flex is achieved by designing the contact spring with a constricted width near the free edge of the armature and broadening into a T-shaped end to provide a double contact or bridge contact. Also, a pair of supporting tabs are used to transmit a jolt of force to the armature during opening of the contacts to break any welding or adhesion of the contacts.
One problem inherent in the above type of relay is that, due to the typical close proximity of the contacts and the core, there is a possibility of voltage breakdown between the contacts and coil during voltage surges. For example, such voltage surges may occur during lightning storms.
Hence, there is a need for an electromagnetic relay with improved resiliency to voltage surges, and which is of a simple and compact design that is readily manufacturable